1. Field of Invention
The present invention relates to power-line-operated overload-protected power distribution systems in general, and to doubly overload-protected high-frequency lighting systems in particular.
2. Description of Prior Art
High-frequency lighting systems have been described in several prior art references, such as for instance in U.S. Pat. No. 4,207,497 to Capewell et al, or in U.S. Pat. No. 4,207,498 to Spira et al. In all of these systems, high-frequency power is distributed in the same fashion as in conventionally done with ordinary low-frequency power supplied directly from the power line. That is, the high-frequency power is distributed from a central source to the various high-frequency lighting fixtures by way of a single pair of output terminals and a single pair of high-frequency conductors--with all the fixtures connected with this single pair of conductors at spaced-apart points therealong.
3. Related Patent Application
The applicant of the present application has a co-pending patent application, Ser. No. 573,423 filed on Jan. 24, 1984, in which is described another form of high-frequency lighting system--a form in which high-frequency power is distributed to a plurality of individual lighting fixtures from a central source by way of a plurality of separate pairs of output terminals and a like plurality of separate pairs of high-frequency conductors. That is, each individual lighting fixture is powered directly from the central source by way of a separate dedicated pair of conductors.
4. Rationale of Invention
When powering a number of lighting fixtures from a central high-frequency source, which normally would comprise electronic converter means, it is important to effectively protect this source against overload--especially in situations where these fixtures contain series-resonant-loaded gas discharge lamps.
This issue has not been effectively dealt with in prior art, and especially not for the case where a plurality of lighting fixtures are separately and individually powered directly from a plurality of separate and individual outputs of a central high-frequency power source.
The instant invention is aimed at providing a cost-effective resolution to this issue.